Set of key buttons for a handset



FIG. 1 is a front view of a set of key buttons for a handset showing my new design;

FIG. 2 is a perspective front view thereof;

FIG. 3 is a front view of a set of key buttons for a handset showing my new design; and,

FIG. 4 is a perspective front view thereof.

The broken line showing of the environmental structures is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a set of key buttons for a handset, as shown and described. 